The invention is based on patent application No. 11-281812 Pat. filed in Japan, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming method of a non-fixing type for forming a toner image on an image receiving sheet as well as a method of reusing an image formation material (an image receiving sheet, toner and/or the like), and also relates to an image forming apparatus and an image receiving sheet which are used for the above methods.
2. Description of the Background Art
Various image forming methods have been employed for forming toner images on image receiving sheets. An electrophotographic image forming method is a typical one among these methods.
According to the electrophotographic image formation, an electrostatic latent image carrier such as a photosensitive member is charged to a predetermined potential, and image exposure is effected on the charged region to form an electrostatic latent image according to original image information. Then, the electrostatic latent image thus formed is developed into a visible toner image with developer. The visible toner image is finally transferred onto the image receiving sheet, and is fixed thereto.
Apart from the above, the image forming method of a direct recording type has been proposed. According to this type, the electrostatic latent image is not formed, and the toner is directly adhered onto the image receiving sheet to form the toner image in accordance with the original image information, and is fixed. Alternatively, the toner image may be directly formed on an intermediate transfer member in a similar manner. The image thus formed is then transferred and fixed onto the image receiving sheet.
In either of the above types, the conventional image forming method uses the toner which can be fixed onto the image receiving sheet. As a typical example of such developer, toner of a hot-melting type, which is formed of pigment or dye dispersed and mixed into thermoplastic resin, may be used.
The toner image formed of the toner of such a hot-melting type is finally melted by the heat applied from a heat roller, infrared ray irradiating device, or the like, and is fixed onto the image receiving sheet made of paper, plastics or the like. If necessary, a pressure is applied during the heating.
The toner fixed onto the image receiving sheet cannot be separated from the image receiving sheet without difficulty, and therefore reuse of the toner and image receiving sheet is difficult. Accordingly, the image receiving sheet having the toner image fixed thereto will be disposed when it becomes unnecessary.
According to progress of the information technology in recent days, large amounts of toner and image receiving sheets have been used, and the energy required for the production of them as well as a carbon dioxide gas discharged thereby have been increasing.
As a method of separating the toner from the transfer sheet(image receiving sheet) for reusing transfer sheets carrying toner images fixed thereto, a deinking method which uses an aqueous solution of, e.g., a surface active agent has been know. However, this requires a large amount of energy for removing water permeated into paper, and the removed toner cannot be reused because it is in the solidified form after melting.
For overcoming the above problems, another manner is already proposed for reusing the image receiving sheet and the toner. In this manner, minute projections are formed and dispersed on a surface of the image receiving sheet. The toner image is transferred onto the irregular surface of the image receiving sheet, and is fixed by a pressure for forming the image. The toner forming the image is separated from the image receiving sheet in a mechanical manner for reusing the image receiving sheet and the toner.
According to the above image forming method and the image receiving sheet, however, the image receiving sheet is handled after the image formation while keeping the toner adhered onto the minute projections on the image receiving sheet. Although the toner adhered to the projections is fixed thereto by the pressing processing after the transfer of the toner image onto the image receiving sheet, the toner must be fixed to the projections only to an extent which allows mechanical removable of the toner from the image receiving sheet in a later processing. Accordingly, when the sheet carrying the image comes into contact with a finger or the like, or is laid over another image receiving sheet or the like, the toner on the projections may adhere onto the finger, the rear surface of the sheet or the like, and thereby smear them.
Since each of the minute projections formed on the image receiving sheet has an independent point-like form, and therefore is liable to be bent or deformed by an external force. Further, projected portions, which are present on an object in contact with the image receiving sheet, are liable to be located between the projections of the image receiving sheet. This disturbs the toner image, and thus prevents sufficient protection of the toner image.
Accordingly, the image forming method and the image receiving sheet described above cannot be practically used without difficulty.
Accordingly, an object of the invention is to provide an image forming method for forming a toner image on an image receiving sheet, and particularly the image forming method of a non-fixing type, in which the toner image is not fixed to the image receiving sheet in contrast to the prior art, the toner image is held for image formation on the image receiving sheet in such a state that allows separation and removal, and thereby allows reuse of the toner removed from the image receiving sheet already subjected to the toner image formation and/or the image receiving sheet.
Another object of the invention is to provide a non-fixing image forming method which can be practically used, and more particularly, the non-fixing image forming method, which can form a toner image in such a manner that the toner image is protected and smearing of a finger or the like in contact with the image receiving sheet is suppressed during ordinary handling of the image receiving sheets (e.g., when viewing the image formed on the sheet, and/or overlaying the sheets for arrangement or the like after the image formation).
Still another object of the invention is to provide a method of reusing an image formation material, which allows separation and removal of toner from an image receiving sheet carrying a toner image, and allows reuse of at least one of the image formation materials such as toner and image receiving sheet.
Yet another object of the invention is to provide an image forming apparatus of a non-fixing type, which can be practically used for the image forming method and the image formation material reusing method according to the invention.
Further another object of the invention is to provide a toner removing device for separating and removing toner from an image receiving sheet, on which a toner image is formed by the image forming method according to the invention.
A further object of the invention is to provide an image receiving sheet, which is suitable to the image forming method and the image formation material reusing method according to the invention.
For achieving the above objects, the inventors have made a study to find the following facts.
(1) For forming a toner image, such an image receiving sheet may have an irregular surface provided with a large number of concavities for receiving or accommodating toner, and the toner may be removably adhered to the concavities of the irregular surface of the image receiving sheet.
(2) The toner adhered to the concavities of the irregular surface of the image receiving sheet may be protected from an external force by convexities of the irregular surface. These concavities may have continuous groove-like forms so that continuous convexities or ridges extending along the continuous groove-like concavities may protect the toner. Thereby, the toner in the concavities can be sufficiently protected during ordinary handling of the image receiving sheet carrying the image, and the toner image, which is not subjected to a conventional fixing, can be maintained as long as a particular toner removing action is not effected thereto.
(3) The toner adhered to tops of the ridges of the irregular surface of the image receiving sheet can be intensively removed after the toner is adhered to the concavities of the irregular surface of the image receiving sheet.
(4) After the toner image was formed on the image receiving sheet, the image receiving sheet and/or the like can be reused by separating and removing the toner from the image receiving sheet. This can be easily performed because the toner is removably adhered to the sheet.
(5) The image receiving sheet may be covered with a protective sheet for further reliably protecting the toner image, and for further reliably suppressing smearing of a hand or finger with toner on the image receiving sheet.
Based on the above findings, the invention provides an image forming method which allows reusing of an image formation material, and also provides an image forming apparatus, a toner removing device and an image receiving sheet used for implementing the above method. These are as follows:
(1) Image Forming Method
An image forming method including the steps of:
supplying to a printing device an image receiving sheet having an irregular surface provided with a large number of continuous groove-like concavities for receiving toner; and
adhering removably a toner image corresponding to an original image to the continuous groove-like concavities of the image receiving sheet by the printing device.
(2) Image Forming Apparatus
(a) An image forming apparatus including:
a device for supplying an image receiving sheet having an irregular surface provided with a large number of continuous groove-like concavities for receiving toner; and
a printing device for removably adhering a toner image corresponding to an original image to the continuous groove-like concavities of the image receiving sheet supplied from the image receiving sheet supply device.
(b) An image forming apparatus including:
a device for supplying an image receiving sheet having an irregular surface provided with a large number of continuous groove-like concavities for receiving toner;
a toner separating device for separating and removing the toner from the image receiving sheet supplied from the image receiving sheet supply device; and
a printing device for removably adhering a toner image corresponding to an original image to the continuous groove-like concavities of the image receiving sheet supplied through the toner separating device.
(3) Toner Removing Device
A toner removing device including:
a device for supplying an image receiving sheet having an irregular surface provided with a large number of continuous groove-like concavities for receiving toner; and
a toner separating device for separating and removing the toner from the image receiving sheet supplied from the image receiving sheet supply device.
(4) Image Receiving Sheet
An image receiving sheet for forming a toner image by removably adhering toner, having an irregular surface provided with a large number of continuous groove-like concavities for receiving the toner, wherein the toner image can be formed by removably adhering the toner to the continuous groove-like concavities, and ridges extending along the continuous groove-like concavities can protect the toner adhered to the continuous groove-like concavities.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.